Retrocausality is meant to explain one of the stranger manifestations of the quantum state, where two entangled particles are moved apart and any changes in one seem to change the other, regardless of the distance between them.

It's unknown how the two particles are able to "communicate" across this distance, and the concept seemed so ridiculous to Albert Einstein that he called it "spooky action at a distance."

Retrocausality, however, says it's not a matter of one particle acting on another across distance; it's about one particle acting on the other across time.

According to retrocausality, decisions made in the present (such as choosing a measurement method for an entangled particle) can retroactively change the properties of the other entangled particle.

"There is a small group of physicists and philosophers that think this idea is worth pursuing, including Huw Price and Ken Wharton [a physics professor at San José State University]," Matthew S. Leifer, of Chapman University, told Phys.org.

"There is not, to my knowledge, a generally agreed upon interpretation of quantum theory that recovers the whole theory and exploits this idea. It is more of an idea for an interpretation at the moment, so I think that other physicists are rightly skeptical, and the onus is on us to flesh out the idea."

Hopefully they find a way to test this theory—otherwise, theoretical physics may have officially become a bunch of scientists sitting around and saying "Wouldn't it be cool if...?"